The proposed 5 year study will test the efficacy of a cognitive- behavioral intervention, based on the Relapse Prevention (RP) model (Marlatt & Gordon, 1985), for decreasing sexual behaviors that put adult heterosexual women at high risk for AIDS and other sexually transmitted diseases (STD). The intervention will be theory directed and empirically grounded, drawing on our decision modeling research and on our experience applying the RP model to safer sex groups for gay and bisexual men. In the first year and one half we will adapt the intervention used with men, test its application in this new population and develop and test a protocol for a standard treatment control group, incorporating education and social support. In the following years, 400 women recruited from an urban STD clinic, and from other community agencies serving high risk women, will be randomly assigned to a sixteen session intervention or to a sixteen session standard treatment control group in 20 cohorts of 20 women each. The RP groups will help women personalize risk, identify their own risk behaviors, develop goals and motivation for change, and learn strategies for change. The groups will be designed to enhance the maintenance of change by helping women learn how to manage behavioral "slips", improve their life-style, and develop social support. An Advisory Board of individuals working with high-risk women will be formed at the start of the project and will be utilized throughout the project. Measures to be used include STD clinical exam and laboratory testing at study entry and at 12 months after intervention, a pretest, a post-test 1 month after the intervention to assess the short-term impact of the intervention, post-tests at 4, 8, and 12 months to assess long-term effectiveness, and skill assessment at study entry, and at 1 and 12 months after intervention. Outcomes assessed will include self-reported cognitive and behavioral data, biological markers of STD acquisition, and ongoing monitoring of medical records for evidence of STD. It is hypothesized that: following treatment, experimental subjects will report greater reductions in unsafe sex acts, greater increases in safer sex practices, more favorable cognitions toward safer sex, better problem-solving skills, and fewer new STDs compared to standard treatment control subjects, and that these changes will be maintained over time. If the intervention proves to be successful, we will work with the Advisory Board to foster the continued availability of the intervention in this community.